In a complete batch type SBR, the cycle is started by Anoxic inflow of municipal wastewater after discharge of treated water, and the denitrification is carried out. The entered wastewater is exhausted as carbon source to enhance the growth conditions of nitrification microorganisms and the aerobic reaction occurs without influx of the wastewater. Also, the wastewater is not flowed in the sedimentation/discharge procedure. Such SBR, which is a complete batch type, has a high sedimentation efficiency and can increase the discharge percent of the treated water.
Omniflo SBR includes a logic control unit and an aeration unit, and can optimize the nitrification and denitrification procedures by controlling the aeration unit by means of DO determination.
Cyclic Activated Sludge System (CASS™) developed by Transenviro, Inc. comprises a selector in an intake, to which the returned sludge is entered. The main denitrification reactions occur at mix tank and by the Anoxic condition inside sludge floc under Aerobic condition. The system has the advantages that the flotation of sludge is avoided since the denitrification by wastewater influx in the sedimentation step is diminished, the growth of filamentous organisms is suppressed and the stirrer is not needed due to the hydraulic stirrability.
In Intermittent Cyclic Extended Aeration System (ICEAS), wherein the influx water is fed continuously in all phases, the main denitrification reactions occur by the Anoxic condition inside sludge floc induced by air on/off. The system consists of a single reactor that comprises a selector of the top region, a main tank of the intermediate region and a sedimentation tank of the bottom. The selector of the top region promotes the growth of the denitrification microorganisms and suppresses the growth of filamentous organisms at the same time of removing the nitrogen.
The SBR reactor, CASS and ICEAS, that have been installed to the conventional municipal wastewater treatment plant, have the disadvantages that the operations thereof are complicated and some organic materials may be discharged in the untreated state in the Anoxic and Anaerobic states. Therefore, there are demands for improvement of the treatment procedures in order to treat the organic materials more completely.